Synchronous Motor Field Alignment Using Incremental Encoder
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing synchronous motor systems face challenges in aligning their magnetic fields effectively during startup, leading to inefficiencies and potential damage due to unknown rotor positions and uncontrollable torque, especially with the use of expensive absolute encoders.
Innovation Solution
A method and system for synchronously matching the magnetic fields of a synchronous motor's first and second parts by generating a magnetic field with the first part in a predetermined orientation, determining the movement direction, and iteratively adjusting the magnetic field orientation based on detected movement, allowing for rough alignment using a cost-effective incremental encoder, followed by fine-tuning to achieve stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an absolute encoder is used to detect rotor position for effective electronic commutation, then the motor can operate with maximum torque utilization, but the system cost increases significantly
Solution Approach 1:
The patent replaces the expensive absolute encoder with a simple incremental encoder that is much cheaper and simpler in structure. The incremental encoder only needs to detect relative position changes during startup, not absolute position, making it a cost-effective substitute that achieves the necessary function without the complexity of an absolute encoder system
Solution Approach 2:
The patent replaces the mechanical/complex electronic absolute encoder system with a simplified approach using an incremental encoder combined with a specific startup procedure. The system uses current pulse application to the stator windings to create magnetic fields that align with the rotor magnets, allowing position detection through current measurements rather than complex encoder hardware
2Ease of operation
If the motor starts without proper magnetic field alignment, then startup is simpler, but uncontrollable torque may cause damage or excessive wear
Solution Approach 1:
The patent applies preliminary action by performing magnetic field alignment before normal motor operation begins. During the startup phase, the controller applies specific current patterns to the stator windings to create magnetic fields that align with the rotor permanent magnets, establishing proper magnetic field orientation before full power operation to prevent damaging torque spikes
Solution Approach 2:
The patent uses periodic action in the startup sequence by applying current pulses to different stator windings in a predetermined sequence. The controller systematically energizes windings in phases, creating a rotating magnetic field that gradually aligns with the rotor position, allowing controlled rotation and alignment without sudden torque shocks
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient and cost-effective alignment of magnetic fields, reducing wear and tear, minimizing unwanted movements, and ensuring smooth operation of synchronous motors with reduced risk of damage, applicable to both rotary and linear motors.
Implementation Method 1
The induction of a movement is based on an interaction of magnetic fields. Here, a rotary or translatory moving magnetic field (rotating field or traveling field) is generated with the first motor part with the help of electromagnets (current-carrying conductors or coils). The second motor part has one or more permanent magnets, so that there is a static magnetic field with respect to the second motor part. The magnetic field of the first motor part interacts with the static field of the second motor part so that the first and second motor parts are moved relative to each other.
Implementation Method 2
In order to generate a moving magnetic field, the electromagnets of the first motor part are controlled in a time-staggered manner or supplied with a current.
Data Source
Figure 1~3
Figure 4A~4C
Figure 5~6
AI summary
The present invention relates to a method for operating a synchronous motor (100, 300). In the method, a magnetic field (111, 311) is created in a specified alignment in a method step a) using the first motor part (110, 310) in order to create a relative movement between the first and second motor part (110, 120, 310, 320) limited to a specified amount (151), and in a method step b), a movement direction of the limited relative movement between the first and second motor part (110, 120, 310, 320) is determined. The method steps a) and b) are repeated until a change of the movement direction of the limited relative movement between the first and second motor part (110, 120, 310, 320), wherein in the method step a) a magnetic field (111, 311) having a changed alignment compared to the previously created magnetic field (111, 311) is created using the first motor part (110, 310), and wherein the alignment of the magnetic field (111, 311) is changed by a specified alignment section (170) and depending on the determined movement direction. The invention further relates to an amplifier (200) for operating a synchronous motor (100, 300) and to a system comprising an amplifier (200) and a synchronous motor (100, 300).